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Choi Y, Koh J, Cha SS, Roe JH. Activation of zinc uptake regulator by zinc binding to three regulatory sites. Nucleic Acids Res 2024; 52:4185-4197. [PMID: 38349033 PMCID: PMC11077047 DOI: 10.1093/nar/gkae079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 05/09/2024] Open
Abstract
Zur is a Fur-family metalloregulator that is widely used to control zinc homeostasis in bacteria. In Streptomyces coelicolor, Zur (ScZur) acts as both a repressor for zinc uptake (znuA) gene and an activator for zinc exporter (zitB) gene. Previous structural studies revealed three zinc ions specifically bound per ScZur monomer; a structural one to allow dimeric architecture and two regulatory ones for DNA-binding activity. In this study, we present evidence that Zur contains a fourth specific zinc-binding site with a key histidine residue (H36), widely conserved among actinobacteria, for regulatory function. Biochemical, genetic, and calorimetric data revealed that H36 is critical for hexameric binding of Zur to the zitB zurbox and further binding to its upstream region required for full activation. A comprehensive thermodynamic model demonstrated that the DNA-binding affinity of Zur to both znuA and zitB zurboxes is remarkably enhanced upon saturation of all three regulatory zinc sites. The model also predicts that the strong coupling between zinc binding and DNA binding equilibria of Zur drives a biphasic activation of the zitB gene in response to a wide concentration change of zinc. Similar mechanisms may be pertinent to other metalloproteins, expanding their response spectrum through binding multiple regulatory metals.
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Affiliation(s)
- Yunchan Choi
- Laboratory of Molecular Microbiology, School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Junseock Koh
- Laboratory of Biophysical Chemistry, School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Sun-Shin Cha
- Protein Research Laboratory, Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jung-Hye Roe
- Laboratory of Molecular Microbiology, School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
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2
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Gu Y, Liu Y, Mao W, Peng Y, Han X, Jin H, Xu J, Chang L, Hou Y, Shen X, Liu X, Yang Y. Functional versatility of Zur in metal homeostasis, motility, biofilm formation, and stress resistance in Yersinia pseudotuberculosis. Microbiol Spectr 2024; 12:e0375623. [PMID: 38534119 PMCID: PMC11064496 DOI: 10.1128/spectrum.03756-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/13/2024] [Indexed: 03/28/2024] Open
Abstract
Zur (zinc uptake regulator) is a significant member of the Fur (ferric uptake regulator) superfamily, which is widely distributed in bacteria. Zur plays crucial roles in zinc homeostasis and influences cell development and environmental adaptation in various species. Yersinia pseudotuberculosis is a Gram-negative enteric that pathogen usually serves as a model organism in pathogenicity studies. The regulatory effects of Zur on the zinc transporter ZnuABC and the protein secretion system T6SS have been documented in Y. pseudotuberculosis. In this study, a comparative transcriptomics analysis between a ∆zur mutant and the wild-type (WT) strain of Y. pseudotuberculosis was conducted using RNA-seq. This analysis revealed global regulation by Zur across multiple functional categories, including membrane transport, cell motility, and molecular and energy metabolism. Additionally, Zur mediates the homeostasis not only of zinc but also ferric and magnesium in vivo. There was a notable decrease in 35 flagellar biosynthesis and assembly-related genes, leading to reduced swimming motility in the ∆zur mutant strain. Furthermore, Zur upregulated multiple simple sugar and oligopeptide transport system genes by directly binding to their promoters. The absence of Zur inhibited biofilm formation as well as reduced resistance to chloramphenicol and acidic stress. This study illustrates the comprehensive regulatory functions of Zur, emphasizing its importance in stress resistance and pathogenicity in Y. pseudotuberculosis. IMPORTANCE Bacteria encounter diverse stresses in the environment and possess essential regulators to modulate the expression of genes in responding to the stresses for better fitness and survival. Zur (zinc uptake regulator) plays a vital role in zinc homeostasis. Studies of Zur from multiple species reviewed that it influences cell development, stress resistance, and virulence of bacteria. Y. pseudotuberculosis is an enteric pathogen that serves a model organism in the study of pathogenicity, virulence factors, and mechanism of environmental adaptation. In this study, transcriptomics analysis of Zur's regulons was conducted in Y. pseudotuberculosis. The functions of Zur as a global regulator in metal homeostasis, motility, nutrient acquisition, glycan metabolism, and nucleotide metabolism, in turn, increasing the biofilm formation, stress resistance, and virulence were reviewed. The importance of Zur in environmental adaptation and pathogenicity of Y. pseudotuberculosis was emphasized.
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Affiliation(s)
- Yanchao Gu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yongde Liu
- Qingyang Longfeng Sponge City Construction Management and Operation Co., Ltd, Qingyang, China
| | - Wei Mao
- Qingyang Longfeng Sponge City Construction Management and Operation Co., Ltd, Qingyang, China
| | - Ying Peng
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xiaoru Han
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Han Jin
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Jingling Xu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Liyang Chang
- College of Enology, Northwest A&F University, Yangling, China
| | - Yixin Hou
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xihui Shen
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xingyu Liu
- General Research Institute for Nonferrous Metals, Beijing, China
| | - Yantao Yang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
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3
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Kompaniiets D, Wang D, Yang Y, Hu Y, Liu B. Structure and molecular mechanism of bacterial transcription activation. Trends Microbiol 2024; 32:379-397. [PMID: 37903670 DOI: 10.1016/j.tim.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 11/01/2023]
Abstract
Transcription activation is an important checkpoint of regulation of gene expression which occurs in response to different intracellular and extracellular signals. The key elements in this signal transduction process are transcription activators, which determine when and how gene expression is activated. Recent structural studies on a considerable number of new transcription activation complexes (TACs) revealed the remarkable mechanistic diversity of transcription activation mediated by different factors, necessitating a review and re-evaluation of the transcription activation mechanisms. In this review, we present a comprehensive summary of transcription activation mechanisms and propose a new, elaborate, and systematic classification of transcription activation mechanisms, primarily based on the structural features of diverse TAC components.
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Affiliation(s)
- Dmytro Kompaniiets
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Dong Wang
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Yang Yang
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Bin Liu
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA.
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4
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Kim M, Le MT, Fan L, Campbell C, Sen S, Capdevila DA, Stemmler TL, Giedroc DP. Characterization of the Zinc Uptake Repressor (Zur) from Acinetobacter baumannii. Biochemistry 2024; 63:660-670. [PMID: 38385972 PMCID: PMC11019503 DOI: 10.1021/acs.biochem.3c00679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Bacterial cells tightly regulate the intracellular concentrations of essential transition metal ions by deploying a panel of metal-regulated transcriptional repressors and activators that bind to operator-promoter regions upstream of regulated genes. Like other zinc uptake regulator (Zur) proteins, Acinetobacter baumannii Zur represses transcription of its regulon when ZnII is replete and binds more weakly to DNA when ZnII is limiting. Previous studies established that Zur proteins are homodimeric and harbor at least two metal sites per protomer or four per dimer. CdII X-ray absorption spectroscopy (XAS) of the Cd2Zn2 AbZur metalloderivative with CdII bound to the allosteric sites reveals a S(N/O)3 first coordination shell. Site-directed mutagenesis suggests that H89 and C100 from the N-terminal DNA binding domain and H107 and E122 from the C-terminal dimerization domain comprise the regulatory metal site. KZn for this allosteric site is 6.0 (±2.2) × 1012 M-1 with a functional "division of labor" among the four metal ligands. N-terminal domain ligands H89 and C100 contribute far more to KZn than H107 and E122, while C100S AbZur uniquely fails to bind to DNA tightly as measured by an in vitro transcription assay. The heterotropic allosteric coupling free energy, ΔGc, is negative, consistent with a higher KZn for the AbZur-DNA complex and defining a bioavailable ZnII set-point of ≈6 × 10-14 M. Small-angle X-ray scattering (SAXS) experiments reveal that only the wild-type Zn homodimer undergoes allosteric switching, while the C100S AbZur fails to switch. These data collectively suggest that switching to a high affinity DNA-binding conformation involves a rotation/translation of one protomer relative to the other in a way that is dependent on the integrity of C100. We place these findings in the context of other Zur proteins and Fur family repressors more broadly.
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Affiliation(s)
- Minyong Kim
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - My Tra Le
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Lixin Fan
- Basic Science Program, Frederick National Laboratory for Cancer Research, SAXS Core Facility of the National Cancer Institute, Frederick, Maryland 21702, United States
| | - Courtney Campbell
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201-2417, United States
| | - Sambuddha Sen
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Daiana A Capdevila
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), C1405 BWE Buenos Aires, Argentina
| | - Timothy L Stemmler
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201-2417, United States
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
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5
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Sarasa-Buisan C, Ochoa de Alda JAG, Velázquez-Suárez C, Rubio MÁ, Gómez-Baena G, Fillat MF, Luque I. An ancient bacterial zinc acquisition system identified from a cyanobacterial exoproteome. PLoS Biol 2024; 22:e3002546. [PMID: 38466754 PMCID: PMC10957091 DOI: 10.1371/journal.pbio.3002546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 03/21/2024] [Accepted: 02/12/2024] [Indexed: 03/13/2024] Open
Abstract
Bacteria have developed fine-tuned responses to cope with potential zinc limitation. The Zur protein is a key player in coordinating this response in most species. Comparative proteomics conducted on the cyanobacterium Anabaena highlighted the more abundant proteins in a zur mutant compared to the wild type. Experimental evidence showed that the exoprotein ZepA mediates zinc uptake. Genomic context of the zepA gene and protein structure prediction provided additional insights on the regulation and putative function of ZepA homologs. Phylogenetic analysis suggests that ZepA represents a primordial system for zinc acquisition that has been conserved for billions of years in a handful of species from distant bacterial lineages. Furthermore, these results show that Zur may have been one of the first regulators of the FUR family to evolve, consistent with the scarcity of zinc in the ecosystems of the Archean eon.
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Affiliation(s)
- Cristina Sarasa-Buisan
- Departamento de Bioquímica y Biología Molecular y Celular e Instituto de Biocomputación y Física de Sistemas Complejos (Bifi), Universidad de Zaragoza, Zaragoza, Spain
| | - Jesús A. G. Ochoa de Alda
- Didáctica de las Ciencias Experimentales y la Matemáticas, Universidad de Extremadura, Cáceres, Spain
| | | | - Miguel Ángel Rubio
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Guadalupe Gómez-Baena
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba, Spain
| | - María F. Fillat
- Departamento de Bioquímica y Biología Molecular y Celular e Instituto de Biocomputación y Física de Sistemas Complejos (Bifi), Universidad de Zaragoza, Zaragoza, Spain
| | - Ignacio Luque
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
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6
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He H, Li Y, Ma X, Xu S, Zhang L, Ding Z, Shi G. Design of a sorbitol-activated nitrogen metabolism-dependent regulatory system for redirection of carbon metabolism flow in Bacillus licheniformis. Nucleic Acids Res 2023; 51:11952-11966. [PMID: 37850640 PMCID: PMC10681722 DOI: 10.1093/nar/gkad859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 09/05/2023] [Accepted: 09/23/2023] [Indexed: 10/19/2023] Open
Abstract
Synthetic regulation of metabolic fluxes has emerged as a common strategy to improve the performance of microbial cell factories. The present regulatory toolboxes predominantly rely on the control and manipulation of carbon pathways. Nitrogen is an essential nutrient that plays a vital role in growth and metabolism. However, the availability of broadly applicable tools based on nitrogen pathways for metabolic regulation remains limited. In this work, we present a novel regulatory system that harnesses signals associated with nitrogen metabolism to redirect excess carbon flux in Bacillus licheniformis. By engineering the native transcription factor GlnR and incorporating a sorbitol-responsive element, we achieved a remarkable 99% inhibition of the expression of the green fluorescent protein reporter gene. Leveraging this system, we identified the optimal redirection point for the overflow carbon flux, resulting in a substantial 79.5% reduction in acetoin accumulation and a 2.6-fold increase in acetate production. This work highlight the significance of nitrogen metabolism in synthetic biology and its valuable contribution to metabolic engineering. Furthermore, our work paves the way for multidimensional metabolic regulation in future synthetic biology endeavors.
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Affiliation(s)
- Hehe He
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
| | - Youran Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
| | - Xufan Ma
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
| | - Sha Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
| | - Liang Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
| | - Zhongyang Ding
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
| | - Guiyang Shi
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
- Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214000, PR China
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7
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Leipart V, Enger Ø, Turcu DC, Dobrovolska O, Drabløs F, Halskau Ø, Amdam GV. Resolving the zinc binding capacity of honey bee vitellogenin and locating its putative binding sites. INSECT MOLECULAR BIOLOGY 2022; 31:810-820. [PMID: 36054587 PMCID: PMC9804912 DOI: 10.1111/imb.12807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
The protein vitellogenin (Vg) plays a central role in lipid transportation in most egg-laying animals. High Vg levels correlate with stress resistance and lifespan potential in honey bees (Apis mellifera). Vg is the primary circulating zinc-carrying protein in honey bees. Zinc is an essential metal ion in numerous biological processes, including the function and structure of many proteins. Measurements of Zn2+ suggest a variable number of ions per Vg molecule in different animal species, but the molecular implications of zinc-binding by this protein are not well-understood. We used inductively coupled plasma mass spectrometry to determine that, on average, each honey bee Vg molecule binds 3 Zn2+ -ions. Our full-length protein structure and sequence analysis revealed seven potential zinc-binding sites. These are located in the β-barrel and α-helical subdomains of the N-terminal domain, the lipid binding site, and the cysteine-rich C-terminal region of unknown function. Interestingly, two potential zinc-binding sites in the β-barrel can support a proposed role for this structure in DNA-binding. Overall, our findings suggest that honey bee Vg bind zinc at several functional regions, indicating that Zn2+ -ions are important for many of the activities of this protein. In addition to being potentially relevant for other egg-laying species, these insights provide a platform for studies of metal ions in bee health, which is of global interest due to recent declines in pollinator numbers.
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Affiliation(s)
- Vilde Leipart
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesAasNorway
| | - Øyvind Enger
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesAasNorway
| | | | | | - Finn Drabløs
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health SciencesNTNU – Norwegian University of Science and TechnologyTrondheimNorway
| | - Øyvind Halskau
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Gro V. Amdam
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesAasNorway
- School of Life SciencesArizona State UniversityTempeArizonaUSA
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8
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Assunção AGL. The F-bZIP-regulated Zn deficiency response in land plants. PLANTA 2022; 256:108. [PMID: 36348172 PMCID: PMC9643250 DOI: 10.1007/s00425-022-04019-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 10/22/2022] [Indexed: 06/16/2023]
Abstract
This review describes zinc sensing and transcriptional regulation of the zinc deficiency response in Arabidopsis, and discusses how their evolutionary conservation in land plants facilitates translational approaches for improving the Zn nutritional value of crop species. Zinc is an essential micronutrient for all living organisms due to its presence in a large number of proteins, as a structural or catalytic cofactor. In plants, zinc homeostasis mechanisms comprise uptake from soil, transport and distribution throughout the plant to provide adequate cellular zinc availability. Here, I discuss the transcriptional regulation of the response to zinc deficiency and the zinc sensing mechanisms in Arabidopsis, and their evolutionary conservation in land plants. The Arabidopsis F-group basic region leucine-zipper (F-bZIP) transcription factors bZIP19 and bZIP23 function simultaneously as sensors of intracellular zinc status, by direct binding of zinc ions, and as the central regulators of the zinc deficiency response, with their target genes including zinc transporters from the ZRT/IRT-like Protein (ZIP) family and nicotianamine synthase enzymes that produce the zinc ligand nicotianamine. I note that this relatively simple mechanism of zinc sensing and regulation, together with the evolutionary conservation of F-bZIP transcription factors across land plants, offer important research opportunities. One of them is to use the F-bZIP-regulated zinc deficiency response as a tractable module for evolutionary and comparative functional studies. Another research opportunity is translational research in crop plants, modulating F-bZIP activity as a molecular switch to enhance zinc accumulation. This should become a useful plant-based solution to alleviate effects of zinc deficiency in soils, which impact crop production and crop zinc content, with consequences for human nutrition globally.
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Affiliation(s)
- Ana G L Assunção
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg, Denmark.
- CIBIO-InBIO, Research Centre in Biodiversity and Genetic Resources, University of Porto, 4485-661, Vairão, Portugal.
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9
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Yang X, Wang Y, Liu G, Deng Z, Lin S, Zheng J. Structural basis of Streptomyces transcription activation by zinc uptake regulator. Nucleic Acids Res 2022; 50:8363-8376. [PMID: 35871291 PMCID: PMC9371925 DOI: 10.1093/nar/gkac627] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 06/30/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022] Open
Abstract
Streptomyces coelicolor (Sc) is a model organism of actinobacteria to study morphological differentiation and production of bioactive metabolites. Sc zinc uptake regulator (Zur) affects both processes by controlling zinc homeostasis. It activates transcription by binding to palindromic Zur-box sequences upstream of −35 elements. Here we deciphered the molecular mechanism by which ScZur interacts with promoter DNA and Sc RNA polymerase (RNAP) by cryo-EM structures and biochemical assays. The ScZur-DNA structures reveal a sequential and cooperative binding of three ScZur dimers surrounding a Zur-box spaced 8 nt upstream from a −35 element. The ScRNAPσHrdB-Zur-DNA structures define protein-protein and protein-DNA interactions involved in the principal housekeeping σHrdB-dependent transcription initiation from a noncanonical promoter with a −10 element lacking the critical adenine residue at position −11 and a TTGCCC −35 element deviating from the canonical TTGACA motif. ScZur interacts with the C-terminal domain of ScRNAP α subunit (αCTD) in a complex structure trapped in an active conformation. Key ScZur-αCTD interfacial residues accounting for ScZur-dependent transcription activation were confirmed by mutational studies. Together, our structural and biochemical results provide a comprehensive model for transcription activation of Zur family regulators.
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Affiliation(s)
- Xu Yang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China
| | - Yiqun Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China
| | - Guiyang Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China
| | - Shuangjun Lin
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China
| | - Jianting Zheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University , Shanghai 200240, China
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10
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Mikhaylina A, Ksibe AZ, Wilkinson RC, Smith D, Marks E, Coverdale JPC, Fülöp V, Scanlan DJ, Blindauer CA. A single sensor controls large variations in zinc quotas in a marine cyanobacterium. Nat Chem Biol 2022; 18:869-877. [PMID: 35681030 PMCID: PMC9337993 DOI: 10.1038/s41589-022-01051-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/05/2022] [Indexed: 11/09/2022]
Abstract
Marine cyanobacteria are critical players in global nutrient cycles that crucially depend on trace metals in metalloenzymes, including zinc for CO2 fixation and phosphorus acquisition. How strains proliferating in the vast oligotrophic ocean gyres thrive at ultra-low zinc concentrations is currently unknown. Using Synechococcus sp. WH8102 as a model we show that its zinc-sensor protein Zur differs from all other known bacterial Zur proteins in overall structure and the location of its sensory zinc site. Uniquely, Synechococcus Zur activates metallothionein gene expression, which supports cellular zinc quotas spanning two orders of magnitude. Thus, a single zinc sensor facilitates growth across pico- to micromolar zinc concentrations with the bonus of banking this precious resource. The resultant ability to grow well at both ultra-low and excess zinc, together with overall lower zinc requirements, likely contribute to the broad ecological distribution of Synechococcus across the global oceans. ![]()
The zinc-sensor protein Zur in a marine cyanobacterium is distinct from those in other bacteria in structure and location of its sensory zinc site, and facilitates growth across a range of zinc concentrations via activation of a metallothionein gene.
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Affiliation(s)
- Alevtina Mikhaylina
- Department of Chemistry, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK
| | - Amira Z Ksibe
- Department of Chemistry, University of Warwick, Coventry, UK.,School of Life Sciences, University of Warwick, Coventry, UK
| | - Rachael C Wilkinson
- School of Life Sciences, University of Warwick, Coventry, UK.,Swansea University Medical School, Swansea, UK
| | - Darbi Smith
- Department of Chemistry, University of Warwick, Coventry, UK
| | - Eleanor Marks
- Department of Chemistry, University of Warwick, Coventry, UK
| | - James P C Coverdale
- Department of Chemistry, University of Warwick, Coventry, UK.,School of Pharmacy, Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| | - Vilmos Fülöp
- School of Life Sciences, University of Warwick, Coventry, UK
| | - David J Scanlan
- School of Life Sciences, University of Warwick, Coventry, UK
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Wang S, Cheng J, Niu Y, Li P, Zhang X, Lin J. Strategies for Zinc Uptake in Pseudomonas aeruginosa at the Host-Pathogen Interface. Front Microbiol 2021; 12:741873. [PMID: 34566943 PMCID: PMC8456098 DOI: 10.3389/fmicb.2021.741873] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
As a structural, catalytic, and signaling component, zinc is necessary for the growth and development of plants, animals, and microorganisms. Zinc is also essential for the growth of pathogenic microorganisms and is involved in their metabolism as well as the regulation of various virulence factors. Additionally, zinc is necessary for infection and colonization of pathogenic microorganisms in the host. Upon infection in healthy organisms, the host sequesters zinc both intracellularly and extracellularly to enhance the immune response and prevent the proliferation and infection of the pathogen. Intracellularly, the host manipulates zinc levels through Zrt/Irt-like protein (ZIP)/ZnT family proteins and various zinc storage proteins. Extracellularly, members of the S100 protein family, such as calgranulin C, sequester zinc to inhibit microbial growth. In the face of these nutritional limitations, bacteria rely on an efficient zinc transport system to maintain zinc supplementation for proliferation and disruption of the host defense system to establish infection. Here, we summarize the strategies for zinc uptake in conditional pathogenic Pseudomonas aeruginosa, including known zinc uptake systems (ZnuABC, HmtA, and ZrmABCD) and the zinc uptake regulator (Zur). In addition, other potential zinc uptake pathways were analyzed. This review systematically summarizes the process of zinc uptake by P. aeruginosa to provide guidance for the development of new drug targets.
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Affiliation(s)
- Shuaitao Wang
- College of Life Sciences, Yan'an University, Yan'an, China
| | - Juanli Cheng
- College of Life Sciences, Yan'an University, Yan'an, China.,Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, China
| | - Yanting Niu
- College of Life Sciences, Yan'an University, Yan'an, China
| | - Panxin Li
- College of Life Sciences, Yan'an University, Yan'an, China
| | - Xiangqian Zhang
- College of Life Sciences, Yan'an University, Yan'an, China.,Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, China
| | - Jinshui Lin
- College of Life Sciences, Yan'an University, Yan'an, China.,Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, China
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